If there was always a positive effect on SQ going forward, then we wouldn't have such a robust 2nd hand market for used gear :P
When you don't like gear at first, and later you do, it's often attributed to burn-in. When you do like gear at first, and later you don't, it seems you were just "ready to try something different".
I'm not saying that burn-in works in reverse, it's just that I think the whole thing is way overblown when it comes to electronics. I had one tech tell me "these caps will sound better with burn-in" after he'd wired them so egregiously WRONG that the amp had a 6dB/octave low frequency rolloff starting all the way up at 1kHz!! Nope, I really don't think burn-in is gonna help much there...
For what it's worth I do believe (and have observed) that break-in can be significant with new speakers & headphones, and to a lesser extent cartridges. It may exist for electronics too, but it's far less significant in my experience.
When you don't like gear at first, and later you do, it's often attributed to burn-in. When you do like gear at first, and later you don't, it seems you were just "ready to try something different".
I'm not saying that burn-in works in reverse, it's just that I think the whole thing is way overblown when it comes to electronics. I had one tech tell me "these caps will sound better with burn-in" after he'd wired them so egregiously WRONG that the amp had a 6dB/octave low frequency rolloff starting all the way up at 1kHz!! Nope, I really don't think burn-in is gonna help much there...
For what it's worth I do believe (and have observed) that break-in can be significant with new speakers & headphones, and to a lesser extent cartridges. It may exist for electronics too, but it's far less significant in my experience.